These studies are designed to explore the role of cell surface lectincarbohydrate interactions, in cellular recognition, co-operation and regulation. Special emphasis is placed on the role of complex carbohydrates and glycoproteins in the regulation of immune response during human pregnancy. A mannose 1-6 dimer of mannose and a more complex glycoprotein of approximate molecular weight 55 kilo daltons have been purified from human pregnancy urine. Both compounds are being extensively characterized for their immunoregulatory properties. A second set of studies is examining a T independent antigen specific model of human antibody production in vitro. These studies are concentrating on 1) cellular requirements, 2) cell subset diversity, and 3) fine specificity of V region products.